printing labels from PeriodicSite in cif file

[AndresOrtegaGuerrero]

Python version

3.12.1

Pymatgen version

2024.3.1

Operating system version

No response

Current behavior

Hello Developers, When defying a Structure where the periodicSites have an specific label , the cif file that is print by CifWriter doesnt use the labels when one is None,

from pymatgen.core import Lattice, Structure, Molecule
from pymatgen.io.cif import CifWriter

coords = [[0, 0, 0], [0.75,0.5,0.75]]
lattice = Lattice.from_parameters(a=3.84, b=3.84, c=3.84, alpha=120,
beta=90, gamma=60)
struct = Structure(lattice, ["Si", "Si"], coords)
struct.sites[0].label = "Si1"

cif_writer = CifWriter(struct)
cif_writer.write_file("output.cif")

I obtained,

_cell_angle_beta 90.00000000
_cell_angle_gamma 60.00000000
_symmetry_Int_Tables_number 1
_chemical_formula_structural Si
_chemical_formula_sum Si2
_cell_volume 40.03858081
cell_formula_units_Z 2
loop
_symmetry_equiv_pos_site_id
symmetry_equiv_pos_as_xyz
1 'x, y, z'
loop
_atom_site_type_symbol
_atom_site_label
_atom_site_symmetry_multiplicity
_atom_site_fract_x
_atom_site_fract_y
_atom_site_fract_z
_atom_site_occupancy
Si Si1 1 0.00000000 0.00000000 0.00000000 1
Si Si1 1 0.75000000 0.50000000 0.75000000 1

Expected Behavior

I should expect

_cell_angle_beta 90.00000000
_cell_angle_gamma 60.00000000
_symmetry_Int_Tables_number 1
_chemical_formula_structural Si
_chemical_formula_sum Si2
_cell_volume 40.03858081
cell_formula_units_Z 2
loop
_symmetry_equiv_pos_site_id
symmetry_equiv_pos_as_xyz
1 'x, y, z'
loop
_atom_site_type_symbol
_atom_site_label
_atom_site_symmetry_multiplicity
_atom_site_fract_x
_atom_site_fract_y
_atom_site_fract_z
_atom_site_occupancy
Si Si1 1 0.00000000 0.00000000 0.00000000 1
Si Si 1 0.75000000 0.50000000 0.75000000 1

Minimal example

No response

Relevant files to reproduce this bug

No response